This invention relates to the field of mounts for optical structures, including but not limited to, reflective panels and hollow retroreflectors.
Optical structures such as, but not limited to, reflective panels (mirror panels) and hollow retroreflectors are old in the art. Hollow retroreflectors are made of three mirror panels joined together preferably having optically flat reflective surfaces disposed at right angles to each other, and meeting at what can be described as a common inside corner of an imaginary cube. Hollow retroreflectors in general have the essential property of causing incident and reflected light rays to travel along substantially parallel paths.
When hollow retroreflectors are assembled for high accuracy and precision it is important to maintain the mutual perpendicularity of the reflective surfaces and sometimes essential to ensure that the retroreflector as a whole does not move. The perpendicularity of the reflective surfaces is affected by external stresses. With regard to high accuracy and precise reflective panels, such as mirror panels to be used for high accuracy purposes, it is also important to try and maintain as optically flat as possible the reflective surface of the panel.
Examples of external stresses that can effect the optical flatness of a reflective panel and/or the perpendicularity of reflective surfaces of abutting reflective panels of a hollow retroreflector, are thermal expansion or contraction of the substrate material from which the panels are made, deflection caused by curing of the adhesives used to join elements together and/or the mass of the panels themselves. Accordingly, it would be desirable to assemble together the elements of a hollow retroreflector and/or to assemble a reflective panel to a mount, in such a manner as to reduce these stresses. It would also be desirable that the manner of mounting a retroreflector to its mount not add to these stresses, but nevertheless, securely retaining the retroreflector on the mount. Examples of hollow retroreflector mounts which have proven successful in maintaining the reflective surfaces in their perpendicular orientations are found in U.S. Pat. No. 3,977,765, to Morton S. Lipkins, 5,122,901, to Zvi Bleier, and 5,335,111, also to Bleier.
The present mount also achieves secure mounting of the optical structure in a manner that greatly reduces deflective stresses on the reflective surface(s) of the structure, while also helping to ensure a secure mount of the structure. For example, it is often important when measuring distances using a retroreflector to reduce to a minimum fluctuations which may occur because of movement of the retroreflector between successive measurements due to the external stresses of mass and/or temperature change. The mount and manner of mounting of the present invention helps to significantly reduce such movement to a minimum.
The mount also allows for easy and secure mounting of the optical structure onto a support structure.